1. Field of the Invention
This invention relates generally to implements for applying liquids to various surfaces, and more particularly to means for automatically sealing the tip end of such implements when not in use so as to provide an air-tight enclosure, and one that will function even when debris is present on the sealing surfaces. In a preferred embodiment, means automatically seal vent means when in the non-use state.
2. Background Art
The types of liquid applicators for which the present invention is intended are varied and generally, but not exclusively, include those which have an extendable element with an application tip at the end thereof to apply a liquid to a surface when in use and which element and tip are retractable within a tubular member when not in use. Such applicators may include fountain pens, "felt tip" markers, ball point pens, and paint and nail polish brushes. Since the liquids employed in these applicators usually have volatile components, it is desirable to provide an air-tight enclosure for the application tip when not in use to prevent evaporation of the volatile components. It is also desirable to seal out dirt and to prevent the unintended contact of the tip with other objects.
There have been a number of attempts in the past to provide sealing means for the ends of the types of liquid applicators generally under consideration here. Usually, each includes a petallate structure which is forced open when the implement is extended to be used and which closes when the tip of the implement is retracted. Known attempts have been described in the following U.S. Pat. Nos.:
______________________________________ Pat. No. Inventor Date Issued ______________________________________ 1,714965 Ullner May 28, 1929 1,839,817 Walker Jan. 5, 1932 2,291,859 Andrews Aug, 4, 1942 2,559,555 Zepelovitch Jul. 3, 1951 3,480,370 Koeln Nov. 25, 1969 4,218,154 Erfer Sep. 10, 1985 4,540,300 Midorikawa Sep. 10, 1985 4,575,271 Hashimoto, et al. Mar. 11, 1986 4,595,307 Heyden Jun. 17, 1986 4,629,348 Hashimoto, et al. Dec. 16, 1986 4,640,637 Winthrop Feb. 3, 1987 ______________________________________
Thus, Ullner describes a cap for a fountain pen, which cap has a petallate closure at the end covering the pen point. The cap is placed over the point end of the fountain pen to cover the point when not in use. When the pen is to be used, the cap is drawn further over the pen barrel with the result that the petals of the end of the cap are forced apart. The petals are described as being of a material, presumably a metallic material, which has spring resilience to normally contract the petals toward each other. It can easily be seen that foreign matter caught between two petals would cause an incomplete seal when the cap is moved to its closed position. It can also be seen that to even approach having an airtight seal without the presence of foreign matter would require careful machining in the manufacturing process.
Walker is similar to Ullner, and differs only in that the petallate closure is more intimately joined with the body of the pen and in that the closure of the petals is assisted by an annular spring mounted circumferentially about the petals. While this device may force closure in spite of softer debris between the petals, it would not do so with harder debris.
Andrews is a relatively complicated variation of Walker and Ullner.
Zepelovitch shows a fountain pen having a resilient plug in the end of a non-petallate opening, the hole in which plug self-closes upon retraction of the point of the pen. While the plug may provide a satisfactory closure for a period of time, it is apparent that, since the point of the pen must be forced through the plug to open the hole, the hole in the plug will eventually wear, thus losing its ability to seal the opening. Additionally, such an arrangement would be unsatisfactory when used with an implement having a soft-tip, such as felt tip pen or a paint or nail polish applicator.
Koeln is a variation of Walker, with the same limitations thereof.
Erfer is also a variation of earlier petallate closure means and has the same limitations.
Midorikawa overcomes some of the limitations of the devices described above, but at the cost of considerable complexity, obviously requiring several manufacturing steps. Additionally, an inherent disadvantage of the design is that the writing element is radially unsupported for a long distance from its tip. In fact, no radial support at all is shown. It is apparent that this arrangement would result in unsatisfactory use in writing when any degree of radial force was exerted on the tip.
Hashimoto '271 discloses a relatively complex sealing arrangement consisting either of a flapper or a ball, either of which could suffer from problems with debris.
Heyden shows a closure for an implement such as a pencil or a pen comprising a resilient retractable sheath placed over the end of the implement. The sheath is drawn back away from the tip of the implement, thus opening a hole in the end of the sheath and exposing the tip. This design depends on the natural resiliency of the sheath for closure of the hole and, therefore, is susceptible to problems resulting from debris in the hole.
Hashimoto et al. '348 is directed to another flapper closure similar to Hashimoto et al. '271.
Winthrop describes a retractable finger nail polish applicator having as a closure a manually placed and removed end cap. This type of closure, which also have been commonly used on various types of writing implements and other liquid applicators, can provide adequate sealing, but has a main disadvantage the fact that there is not protection once the cap is lost. Additionally, an implement with such a closure is not as convenient to use as one with automatic closure means.
Accordingly, it is a principal object of the present invention to provide automatic closure means for retractable liquid applicators which provides an air-tight, or hermetic, seal.
It is also an object of the present invention to provide such closure means that will furnish a hermetic seal even with the presence of some debris in the closure means.
It is another object of the present invention to provide such closure means that is easily manufactured, with a minimum number of parts, and without the necessity of providing close tolerances.
It is a further object of the present invention to provide such closure means that has no contact with the tip of the applicator while the closure means is opening and closing.
It is an additional object of the present invention to provide such closure means that allows for automatic sealing of the vent hole of the applicator while such applicator is not in use.
It is yet a further object of the present invention to provide such closure means for a nonretractable applicator that is moved between sealed and open positions.
Other objects of the present invention will in part be apparent and will in part appear hereinafter.